Question and Answer | Additional Question | Vocabulary | Pictures Done by Angellica S.

Question and Answer

1. Move and manipulate the various appendages. Describe their movement. What do you find interesting about each of these?
   1. Pig--One muscle flexes to pull a limb toward the body. Another one will move to pull it straight. I find it interesting that the muscles seem to only be able to pull, they can't push an appendage straight.
   2. Starfish--Muscles in the body allow movement by pushing out or retracting the hundred of little feet found on a starfish. The muscles seem interesting here because they really aren't that extensive, unlike the other two.
   3. Crayfish--When the tail is straightened one muscle (extensor muscles) flexes, when it is curled that one relaxes and one on the bottom (flexor muscles) flexes instead. It is interesting that this is closer to the pig, even if there don't seem to be as many muscles.
2. Where do the muscles attach to the bones?
   1. Muscles attach at the origin (see vocab) and the insertion point (vocab)
3. How does where they attach determine the movement of the appendage?
   1. The origin is kind of like an anchor. It holds the base of the muscle in place and won't be moved by the contraction of the muscle. From there the muscle will stretch down a bone, ligament, or tendon and connect to another one. That connection is called the insertion point. The muscle will pull that bone toward the origin. For example, in a human, the bicep's origin is almost at the shoulder blade. It's insertion point is on the same side as the crease of your elbow and attached to a bone in the forearm. When you flex it, the muscle pulls your forearm up toward the origin. On the opposite side are the triceps. It is relaxed when the bicep is contracting. This makes up an antagonistic pair or muscles, pulling the arm straight while the bicep makes it bend.
   2. Muscles may also help stabilize parts of the body. These muscles help keep your body parts in place and prevent damage while you are moving. They also offer support. An example of these muscles in humans would be the core muscles. The first layer is muscle that stabilizes and supports the individual segments in the body while the second layer promotes spinal movement.
4. What are some of the differences between the muscle and the tissue where the muscle attaches to the bone?
   1. Muscle is attached to the bone by a tough, fibrous tissue called a tendon. Muscles are moved by the brain and work to move a certain part of the body. Tendons, however, are meant only to attach the muscle to the bone so that muscle movement works properly.
5. Are there differences in the way different muscles attach within the same organism?
   1. Yes
6. How are the attachments of the muscles similar and different among all the organisms including human muscles?
   1. Pigs are very similar to humans in terms of muscles. They have many of the same muscles we do. Like the pectoral muscles that control movement in the chest. However, these may be located in different areas on the body. An example would be the Achielles tendon which is above their knee joint and not at the ankle like ours. With crayfish, their muscles attach to the skeleton differently. This is because crayfish have an exoskeleton so the mover muscles have to be on the outside to move softer parts that could be "joints." This is very different from both humans and pigs which have endoskeletons and muscles over top of the bones that support the body. Starfish are also far different. Their bones and muscles constantly require water to function. They are used to move just like with the other organisms but they are also attached differently.
7. What composes the tissue that connects the muscle to the bone?
   1. Tendons hold muscles to bones. They are made out of collagen fibers. Collagen is a type of protein found exclusively in animals. It makes up hair, nails, muscles, bones, corneas, and a whole bunch of things in animals.

Additional Question

1. What are striated muscle tissues?
   1. Striated muscles are fibers that are combined into parallel fibers. They appear striped and are named after this (striated is just a fancy kinda word for striped).

Vocabulary

Tendon: Tough band connecting muscle to bone
Ligament: A sheet or band of tough that connects bones or cartilage at a joint or supports an organ, muscle, or other body part
Origin: Place where a muscle is attached
Insertion: Point of attachment to the bone the muscle moves.
Belly (of muscle): The bulge of a muscle (widest part)
Abduction: Pulling of a muscle away from the midpoint or midline of the body or limb
Adduction: Pull something toward the middle/center
Extension: When the muscle is stretched out straight
Flexion: Bending a limb or joint

Pictures

Muscles in Pig

Isolating a muscle

The gel-like substance seen here are muscles in the starfish.

Here are muscles found in the tail of he crayfish.